Clothes dryer



Aug. 30, 1960 w. R. STEVENSON ETAL 2,950,539

CLOTHES DRYER Filed on. 10, 1957 ZZ/cZZZEf/Tfifeaemson United States Patent C CLOTHES DRYER Walter R. Stevenson, Efiingham, 111., and William P. Yanik, Melvindale, Mich., assignors to Borg-Warner Corporation, Chicago, 111., a corporation of Illinois Filed Oct. 10, 1957, Ser. No. 689,409

4 Claims. (CI. 34-45) The present invention relates to automatic clothes drying machines and more particularly to a signalling device for a domestic clothes dryer for indicating when the lint filter therefor is clogged and needs to be removed for cleaning.

The conventional domestic clothes dryer comprises, in general, a rotatable clothes receiving drum disposed within a heated casing, and a fan for circulating heated air within the casing to remove moisture from the clothing. The moist, hot air from the casing is exhausted through suitable duct Work either into the room or to the outside thereof. A considerable amount of lint is removed from the clothes during the drying thereof and is carried by the exhausted air. Whether the dryer is vented into the room or to the outside, the lint must be removed from the exhausted air. A filter is therefore placed at some point in the duct work of the dryer to remove the lint from the exhausted air. The filter must be periodically removed and cleaned; otherwise the lint will accumulate thereon to such an extent that the flow of air from the dryer will be substantially impeded, thereby reducing the efficiency of the dryer. The amount of lint which is separated from the exhausted air by the filter will depend on many factors including the type of materials dried, the extent of the dryness, etc. While the filter need not be cleaned after every drying operation, it is necessary that it be cleaned periodically, and it is preferable that the operator know when the filter should be removed and cleaned.

It is therefore an object of the present invention to provide a device which will warn the operator that lint has accumulated on the filter to a point to where it should be removed and cleaned.

It has been found that the lint filter of a particular dryer should be cleaned after about six drying cycles. be understood, of course, that the number of cycles that any particular dryer filter will need to be cleaned will depend on the size of the filter and other factors, and the present invention is not intended to be limited to any particular number of drying cycles.

The object of the present invention is accomplished by an indicating circuit associated with the filter and the timer of the dryer- The circuit comprises a first switch which is adapted to be actuated by the timer of the dryer; a second switch which is associated with the filter of the dryer; and an indicating lamp. The filter switch is adapted to be closed when the filter is in place and the timer operated switch is adapted to be normally open. The timer operated switch has associated therewith a holding relay so that once the switch is actuated to close the electrical circuit and light the lamp, it will remain closed until the filter is removed to open the filter switch and the circuit. The timer operated switch is adapted to be closed by an arm which is actuated by a rotatable cammed wheel, which wheel is rotated to a cam actuating position by a rotated disc on the timer motor shaft.

The invention consists of the novel constructions, arrangements and devices to be hereinafter described and It will Patented Aug. 36, 1960 ICQ claimed for carrying out the above stated object and such other objects as will be apparent from the following description of preferred embodiments of the invention illustrated with reference to the accompanying drawing, wherein:

Fig. 1 is an elcvational view in section showing a clothes dryer with which the present signalling means is associated, and

Fig. 2 is a schematic illustration of the electrical circuit for the signalling means.

Referring to Fig. 1 of the drawing, there is disclosed a clothes dryer with which the present signalling device may be associated. The presently disclosed dryer structure except for the signalling device is fully disclosed in Reiter Patent No. 2,798,306. The dryer comprises an outer casing 10 in which is disposed a rotatable imperforate cylinder 11. The casing 10 comprises a front wall 12, a rear wall 13, a top wall 14, and a bottom wall 15. An opening 16 is provided in the front wall 12 and an opening 17 is provided in the cylinder 11 in re istry therewith whereby clothes may be inserted through the openings into the cylinder 11. A door 18 closes the opening 16.

The cylinder 11 comprises a metal shell 20 made of a solid, imperforate piece of metal, a forward drum end 21 suitably secured to the front end of the cylindrical shell 2(i and a portion of which is bent over the cylindrical shell 20 to define a tire 22, and said front drum end 21 defining a curved ring 23 provided with a perforated flange 24 extending radially inwardly toward the axis of the cylindrical shell 29, and a rear end 25 having a central aperture 26 defined by an inturned flange 27, said rear end 25 of said drum having secured thereto a wall 28' projecting into the cylindrical shell 20 and adapted to define an annular chamber 29. An opening 30 is provided in the rear end 25 of the cylindrical shell 20 and a U-shaped wire 31 suitably covers this opening. The rear end of the cylinder 11 is supported within the casing 10 by means of a shaft 33 rotatably secured to a bracket 34 and a supporting structure 35, and the front of the cylinder is supported by driving wheels or rollers 36 engaging the tire 22 and adapted to be driven by a pulley 37 through a shaft 38.

A fan as for the present dryer is mounted on a sleeve or hub 41 which is co-axial with the supporting shaft 33. A drive pulley 42 is attached to and drives the hub 41. The pulleys 37 and 42 are adapted to be driven by an electric motor (not shown). The fan 49 has a plurality of blades 43 in equally spaced relationship and disposed within the chamber 29. A heater element 44 for the dryer is disposed in a housing 45 formed of metal plates and providing a bafile 46. A plurality of apertures 47 are disposed in the rear wall 13 of the casing 10 and ambient air is drawn by the fan 40 through the apertures 47 in the direction indicated by the arrows over the heater element 44, through an opening 48 in the supporting structure 35, through the opening 26 and the opening 30 into the cylinder 11 and out through the perforated flange 24 and into an exhaust duct 50. A filter 51 is provided in the exhaust duct 5% and suitable access is provided through the casing wall for the insertion and removal of the filter.

Referring to Fig. 2, there is disclosed a conventional timer 60 such as disclosed in Patent No. 2,798,306 which drives a shaft 61 having a disc 62 splined thereto. The shaft 61 also carries a conventional timing cam (not shown). The disc 62 has attached thereto an arm 63 whose end extends beyond the periphery of the disc. Positioned beside the disc 62 is a wheel 64 rotatably supported on a shaft 65 and having fixed to the face thereof a plurality of axially extending pins 66. A cam 67 is formed on the periphery of the wheel 64 and said cam is adapted to engage an actuating arm 68 for a switch 70 for each 360 of rotation of the wheel 64. The switch 70 is normally urged toward an open position by a spring 71. A solenoid 72 is attached to the switch 70 by means of an arm 73. An indicating lamp 74, which maybe appropriately placed on a backguardor control panel 75, and a switch 76 in the-duct 50 *andnormally closed by the filter 51 complete the circuit for" the signalling means. It is to be understood that 'the' presently disclosed signalling circuit is added to the mainjclothe's' dryer circuit disclosed in Patent No. 2,798,3( 6.-' The signalling circuit obviously can be added to any'cloth'es dryer circuit. In operation, a knob 75a on the gamer panel 75 is turned to initiate the drying operation and the disc 62 will rotate as the time isrun off the timer. As'the arm 63 of the disc 62 approaches 270 rotation inthe clock wise direction as seen in Fig. 2, the arm will come into contact with one of the pins 66 and advance the pin 60 (where there are six pins as shown). 1 After six complete revolutions, the arm 63 will have advanced the wheel 64 a complete revolution and the cam 67 will move the arm 68 to actuate the switch 70 into engagement. Since the filter 51 is in place in the duct '50 at this time, the switch 76 will be closed and the engagement of the switch 70 therefore completes the circuit to energize the lamp 74 and warn the operator that the filter should be changed; The completion of the circuit by the switch 70 also energizes the solenoid 72 whereby'the switch will remain in its closed position and the lamp continue to burn after I 7 a warning the operator of a clothes dryer when the filter should be cleaned or changed.

While we have described our invention in connection with one specific embodiment thereof, it is to be understood that this is by way of illustration and not by way of limitation and the scope of our invention is defined solely by the appended claims which should be construed as broadly as the prior art will permit.

We claim:

1. A clothes dryer comprising a casing having an air inlet and an air outlet and having a removable filter in said outlet, a clothes receiving cylinder mounted for rotation in said casing, air heating means, air circulating means, a timer for controlling the operation of said air heating means and said air circulating means, said timer including a driven shaft, means operative in response to the rotation of said timer shaft a predetermined plurality of times to'operate a signal, said last named means comprising an auxiliary circuit for said dryer and including a normally open switch, a normally closed switch, and a signal means in series With said switches, said normally open switch being adapted to be closed by said timer shaft after said predetermined plurality of rotations of said shaft to complete said circuit to operate said signal means,

2. A clothes dryer comprising a casing having an air inlet and an air outlet and having a removable filter in said outlet which must be periodically removed and cleaned, a clothes receiving cylinder mounted for rotation in said casing, air heating means, air circulating means, a timer for controlling the operation of said air heating means and said air circulating means, said timer including a driven shaft, an auxiliary electric circuit including a first switch, a second switch, and a signal means in series with said switches, said first switch being normally open, said second switch being associated with said filter and being normally closed by the filter when it is'in said outlet and being opened when said filter is removed from said outlet,

a relay in series with said switches and signal means and operatively associated with said first switch, means operative in response to the rotation of said timer shaft a predetermined plurality of times to close said first switch to complete said auxiliary circuit holding said relay and energizing'said relay whereby the signal means will remain energized until the filter is removed to open said second switch and break said circuit.

3. A clothes dryer comprising a casing having an air inlet and an air outlet and having a removable filter in said outlet which must be periodically removed and cleaned, a clothes receiving cylinder mounted for rotation in said casing, air heating means, air circulating means, a timer for controlling the operation of said air heating means and said air circulating means, said timer including a driven shaft, an auxiliary electric circuit including a first switch, a second switch, and a lamp in series with said switches, said first switch being normally open, said second switch being associated with said filter and being normally closed by the filter when it is in said outlet and being opened when said filter is removed from said outlet, a relay in series with said switches and lamp and operatively associated with said first switch, means operative in response to the rotation of said timer shaft a predetermined plurality of times to close said first switch to complete said auxiliary circuit holding said relay and removed from said outlet to terminate said signal means;

and said normally closed switch being adapted to be energizing said relay whereby the lamp will remain energized until the filter is removed to open said second switch and break said circuit.

4. A clothes dryer or the like comprising a casing having an air inlet and an air outlet and having a removable filter in said air outlet, a timer for controlling the drying period of said dryer, an auxiliary electrical circuit, signal means in said circuit, means responsive to the operation of said timer to operate said signal means after a predetermined number of drying operations, and a normally open switch in said circuit and adapted to be closed by said filter, said switch being opened when said filter is References Cited in the file of this patent 

